This invention relates to a cassette loading device of front loading type such as a DAT (digital audio tape) cassette loading device for a vehicle.
FIG. 12 is an exploded perspective view of a conventional cassette loading device disclosed by Japanese Patent Application (OPI) No. 270155/1990 (the term "OPI" as used herein means an "unexamined published application"). In FIG. 12, reference numeral 1 designates a DAT cassette incorporating a magnetic tape (hereinafter referred to merely as "a cassette", when applicable); 1a, a fitting part formed on the cassette 1; 1b, a slider; 2, a cassette holder which, while holding a cassette 1, is moved between a cassette inserting position and a cassette loading position; and 4, an elastic engaging member whose base end portion is connected to the cassette holder 2. The elastic engaging member 4 is to be locked to the fitting part 1a, and comprises a hook 4b secured to the end of the leaf spring 4a to be urged toward cassette holder 2. Further in FIG. 12, reference numeral 7 designates a frame U-shaped in section for guiding the cassette holder; 7a, L-shaped guide grooves formed in both side walls of the frame 7; 2d, guide pins protruded from both side walls of the cassette holder 2, the guide pins being moved along the guide grooves 7a, respectively; and 20, disengaging members secured to the frame 7 to disengage the hook 4b from the fitting part 1a of the cassette 1.
FIG. 13 is an exploded perspective view of the frame 7 set upside down in FIG. 12. In FIG. 13, reference numeral 15 designates a slide lever which is moved abutting against the front end face of the cassette 1; 16, a slide plate provided below the slide lever 15 and mounted movably on the upper surface (which is the lower surface in FIG. 12) of the frame 7 with the aid of guide pins 21, the slide plate 16 having plate holes 16a and a slide hole 16b; 15a, a guide protrusion formed on the lower surface of the slide lever 15 and moved along the slide hole 16b of the slide plate 16; 15b, pushing parts provided at the front end of the slide lever 15 to abut against the front end face of the cassette 1; and 15c, an arm provided on one side of the slide lever 15, to abut against a protrusion 2e of the cassette holder 2.
Further in FIG. 13, reference numeral 18 designates a swing lever rotatably supported on a first post 22 which is protruded from the upper surface of the frame 7; and 18a, a loose hole formed in the end portion of the swing lever 18 and engaged with a pin 15d provided on the upper surface of the slide lever 15; and 19, a reversing spring connected between the base end of the swing lever 18 and a second post 23 on the upper surface of the frame 7.
Now, the cassette loading operation of the cassette loading device thus constructed will be described with reference to FIGS. 14 through 18.
In the cassette loading operation, the cassette 1 is inserted into the cassette holder 2 as shown in FIG. 14; that is, the cassette 1 is held abutting against the pushing parts 15b provided at the front end of the slide lever 15. In this case, the hook 4b of the elastic engaging member 4 rides on the disengaging members 20, so that the cassette 1 can be removed if necessary. This position of the cassette 1 as shown in FIGS. 14 and 15 will be referred to as "a first cassette insertion position".
Thereafter, when the cassette 1 is further pushed in the direction of the arrow E manually, pawls 2c of the cassette holder 2 abut against the slider 1b of the cassette 1 to open it, and the hook 4b leaves the disengaging members 20 and engages with the fitting part 1a of the cassette 1 as shown in FIG. 16. This position of the cassette will be referred to as "a second cassette insertion position". When the cassette 1 is pushed in the direction of the arrow F in FIG. 17, the slide lever 15 is guided by the guide protrusion 15a loosely engaged with the slide hole 16b, thus striking a start switch (not shown) against the elastic force of the reversing spring 19.
When the start switch is operated in this manner, cassette holder moving means (not shown) is activated, so that while the guide pins 2d are moved along the guide grooves 7a, the cassette 1 and the cassette holder 2 are moved, as one unit, in the direction of the arrow F. In this operation, the slide lever 15 is moved in the same direction as the cassette holder. In association with the movement of the slide lever, the swing lever 18 is turned in the direction of the arrow G with the aid of the pin 15d of the slide lever 15. When the reversing spring 19 has passed through the toggle point, the slide lever 15 is disengaged from the cassette 1 by the elastic force. In this operation, the guide protrusion 15a abuts against the end wall of the slide hole 16b, so that the slide lever 15 and the slide plate 16 are moved as one unit. Thereafter, the cassette holder 2 and the cassette 1 are moved downwardly to a predetermined loading position as shown in FIG. 18.
Now, the cassette ejecting operation of the cassette loading device will be described.
The cassette 1 and the cassette holder 2 are moved in the directions opposite to those described above. With the slider 1b of the cassette 1 opened, the cassette is moved to the second cassette insertion position. Thereafter, the hook 4b is caused to ride on the disengaging members 20 to permit the removal of the cassette 1. During the movement of the cassette, the protrusion 2e of the cassette holder 2 moved by moving means (not shown) is abutted against the arm 15c of the slide lever 15, to push the latter 15 towards the cassette insertion position. As the slide lever 15 is moved in this manner, the swing lever 18 is turned in the direction of the arrow H. When the reversing spring 19 has passed through the toggle point, with the aid of the elastic force the pushing parts 15b push the front end face of the cassette 1 which is ready to be removed, to close the slider 1b. Thus, the cassette is pushed out to the first cassette insertion position shown in FIGS. 14 and 15.
The conventional cassette loading device is designed as described above. In the cassette loading operation, the manual operation of pushing the cassette is utilized to open the slider of the cassette, and to push the slide lever against the elastic force of the reversing spring to turn the swing lever thereby to turn on the start switch. Hence, a stroke of manual pushing of the cassette is long, and a force required for pushing the cassette is large. That is, with the conventional cassette loading device, insertion of the cassette feels unacceptable.
Furthermore, in the cassette ejecting operation, the reversing spring releases its elastic force abruptly when it has passed through the toggle point. Therefore, the inertial forces of the slide lever and the swing lever are added to the elastic force of the reversing spring, so that the cassette is ejected too much. As a result, the cassette may fall off the cassette holder, or the slide lever strikes against the cassette, thus producing big striking sounds. This may degrade the product.